A trans man or transgender man is a man who was assigned female at birth. Trans men have a male gender identity, and many trans men undergo medical and social transition to alter their appearance in a way that aligns with their gender identity or alleviates gender dysphoria.
Transition among trans men can involve a variety of social, medical, and legal steps. Initially, the term referred specifically to those undergoing hormone replacement therapy (HRT) or sex reassignment surgery (SRS), but its meaning has expanded to include psychological development and self-acceptance. While some trans men pursue medical interventions like hormones and surgery, others may opt out due to personal choice or financial constraints. Many who do not undergo top surgery use chest binding, and some employ packing to create a masculine shape. Transitioning can include social changes, such as adopting a new name and pronouns, legal name change or other document updates, and medical transition with HRT or surgery. Achieving social acceptance as male may be challenging without physical transition, and some trans men may selectively present as female in certain situations. Additionally, some transmasculine individuals may choose to become pregnant, give birth, and breastfeed.